Depends on what you mean by "better". 5.03 is the graphical client so some people find it easier to use, plus you can watch a visual representation of the work via the screen saver. 5.04 is the text-only console which takes fewer system resources and completes WU somwhat faster.

Until yesterday the X1950's worked with the graphical beta version, but no more until the driver is sorted for it to work! I am just using the console version now until it is fixed, I found the graphical version much faster for completing units

There is more info about the following at F@H forum- If you have a x1900xt/xtx, x1950, x1800, x1600, or "maybe" x1650 you can use the gpu version and fold much faster. But yeah the average cpu and average work units take like ~24 hours~.

Also I think that if you are a gamer any open gl game will fail to start if you have the graphical(screensaver type) version of F@H running at the same time as an OpenGl game.

Here is another example of how using a single core cpu with hyper-threading running two clients of F@H can slow down the progress of stanford university's work on the F@H program- This is from Vijay Pande, the head guy.
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Of course, the HT machines would have 2x as many simulations. However, if the minimum number of generations is high (as it is in many of our newer, more complex simulations), having 2x as many useless simulations is still useless.

I am re-starting one of the clients on my hyperthreaded PC with the -oneunit flag so it sends in the results and doesn't download another one. Then after the results are sent I will delete my 2nd console-text-only version folder and continue folding from my original folder.